Great noise gate, only used in the studio! The G400 is a professional 4 channel noise gate that can be operated as 4 separate processors or linked as two independent stereo pairs. In Link mode, Channel 1 and 3 provide Master control and 'rms summing' is used to ensure that signals from both the linked channels operate the gate. Each channel has fully variable controls for Filter Frequency, Threshold and Release. Range is switchable to provide either full muting (-80dBu) or a more subtle level of signal attenuation (-20dBu). Two Attack modes are available; Fast or Slow and Release is manually adjustable. In-built sidechain 'auto-level-sensing' and Hold circuitry ensure that false triggering and chatter are kept to a minimum. High and Low pass filters are included and can be used for wide range of frequency conscious gating applications. [such as noisy guitar pickups etc.] A LISTEN facility allows the filters to be easily tuned by ear. Each channel also has a sidechain insert with front panel indication when an External Key jack is plugged in. LED indicators are provided for Above-Below Threshold, Bypass and Link. All inputs and outputs are electronically balanced and can be switched between +4dBu and -10dBV operating levels.